The painting was owned by Cardinal Fabrizio Spada (1643 –1717) and mentioned in the inventory of his estate in 1717 as “another oversized painting with gilded frame, depicting the slaughter of the innocents” (Cannatà and Vicini [1992], pp. 128 and 145). It was hung in the “vaulted room which leads to the steps to the garden”, in other words in the fourth hall of the museum. The slaughter is summed up in the gesture of the rogue transfixing the body of a child after having cut off the head of his twin, still tightly clutched in the arms of the mother. Scattered drops of blood tie in with similar scenes in the dark background on the left. This is a faithful representation of the fifty-eighth octavo of the work of the same name by G. Battista Marino, published posthumously in 1630 (Cropper 1988). The artist made five preparatory drawings for the work: four are now in the National Galleries of Scotland, and the other in the Nasjonalgalleriet in Oslo. The figure of the executioner, which is not dissimilar from the one in the Martyrdom of St Erasmus by Nicolas Poussin in the Vatican Museums, appears to be inspired by the young gravedigger in the Funeral of St Petronilla by Guercino in the Museo Capitolino in Rome. The young woman with the lamb and the garland of flowers on her head who appears in the clouds surrounded by festive putti, almost as though attempting to stop the slaughter with her arm is considered by many scholars to represent St Agnes but is the personification of Innocence.